| 摘要 |
A shuttle bobbin (1) for sewing machines having a first (11) and second (12) disc-shaped end walls concentrically and integrally formed at both ends of a hub. The diameter of the first end wall (11) being larger than that of the second end wall (12). A partition wall (13) is concentrically and integrally formed at an intermediate portion of the hub, thus partitioning the hub into firsts and second winding parts (15a, 15b). The partition wall (13) is smoothly toothed (13a, 13b) at its outside edges, thus having rounded teeth and rounded roots at the outside edges. The diameter of the addendum circle of the toothed partition wall (13) is equal to the diameter of the first end wall (11) while the diameter of the deddendum circle is equal to the second end wall (12). The second winding part (15b), defined by the second end wall and the partition wall, is positioned just under the lowest position of a sewing needle when the bobbin is installed in a sewing machine. The thread carrying capacity of the above shuttle bobbin (1) is thus increased by the capacity, offered by the second winding part (15b), in comparison with a typical shuttle bobbin.
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